Ice skate sharpening device

ABSTRACT

A portable ice skate sharpening device in the form of an attachment for a conventional hand drill and including a rotary abrasive grinding wheel which is enclosed in a casing having formed therein an opening which exposes a limited portion of the periphery of the rotating wheel and renders the same accessible for application thereto of a skate blade. A removable skate blade positioning unit is positioned within the opening and defines a guide slot through which the skate blade to be sharpened is manually guided to draw the edge of the blade progressively and transversely across the periphery of the wheel, the unit being so designed that the lateral thrust which is applied to the blade incident to its contact with the rotating wheel serves to bring the general plane of the skate blade into coincidence with the axis of rotation of the wheel, thus resulting in a hollow ground skate blade edge the radius of curvature of which lies precisely in the midplane of the skate blade.

United States Patent [191 [111 3,812,626

Thompson 1 May 28, 1974 ICE SKATE SHARPENING DEVICE [76] Inventor:Arnold M. Thompson, Box 172A [57] ABSTRACT Gary Ave., Wheaton, Ill.60090 A portable ice skate sharpening device in the form of anattachment for a conventional hand drill and in- [22] Filed Sept 1972cluding a rotary abrasive grinding wheel which is en- [21] Appl. No.:285,627 closed in a casing having formed therein an opening which exoses a limited portion of the periphery of h h l d d h 'b] f t erotatmgw ee an ren erst e same accessi e or [52] U.S.Cl 51/170PT,5l/l02, 51/228 application thereto of a Skate blade A removable [51]Int. Cl B24b 9/04, B24b 23/02 [58] Field of Search 5] 70 R 170 PT 102skate blade positioning unit 18 positioned within the 1, opening anddefines a guide slot through which the skate blade to be sharpened ismanually guided to [56] References Cited draw the edge of the bladeprogressively and transversely across the periphery of the wheel, theunit UNITED STATES PATENTS being so designed that the lateral thrustwhich is ap- 522,373 7/1894 Hosack 51/102 UX plied to the blade incidentto its contact with the ro- 2,563,013 8/1951 Fell!) 51/102 tating wheelserves to bring the general plane of the g g z skate blade intocoincidence with the axis of rotation o nson 2,906,067 9/1959 Hale51/170 PT of the wheel thus resumng m a hollow ground Skate PrimaryExaminer-Donald G. Kelly Attorney, Agent, or FirmNorman l-l. Gerlachblade edge the radius of curvature of which lies precisely in themidplane of the skate blade.

9 Claims, 15 Drawing Figures 1 ICE SKATE SHARPENING DEVICE The improvedice skate sharpening device comprising the present invention is designedfor use primarily as a portable electric hand drill attachment whichrequires no bench support when in use. The device also is primarilyintended for home use by skate owners and it is so constructed that itmay be manipulated by an operator who, with one hand, may steady thedevice, while with the other hand, the skate blade undergoing sharpeningmay be operatively drawn progressively across the periphery of arotating abrasive grinding wheel which derives its rotary motion fromthe chuck which is associated with the portable hand drill. Theinvention is, however, capable of other uses and the same may, ifdesired and with or without modification as required, be designed forbench use wherein the device is fixedly clamped to a suitable bench,stand, or other support and the abrasive wheel is caused to derive itsrotary motion from a rotary lathe or other chuck or from any suitablecoupling whereby rotary motion is imparted to the abrasive wheel.Irrespective, however, of the particular use to which the presentinvention may be put, the essential features of the invention are at alltimes preserved.

Present day ice skate sharpening devices which are intended for home useor for use in the field are fairly well standardized and they consist ofan elongated tubular'shell which encloses a cylindrical abrasive elementor stone of rod-like design, the shell being slotted longitudinally soas to expose a limited peripheral area of the abrasive element. Skateblade sharpening operations are performed by the simple expedient ofdrawing the skate blade progressively through the slot in the shellwhile at the same time causing the blade edge undergoing sharpening toslide longitudinally along the abrasive element. Such skate bladesharpening devices are possessed of certain limitations, principal amongwhich is the inability thereof to produce linearly straight, parallel,and uniformly sharp ice-cutting edges on opposite sides of the hollowground curvature which extends along the skating surface or edge of theblade. In order to accommodate varying widths of skate blades such asobtain where figure skates, hockey skates, and racing skates areconcerned, the blade? receiving slot is invariably made of a width whichwill accommodate the widest of such blades. Actually, such slot is madea few thousandths of an inch wider than the width of the widest blade sothat there will be a clearance for ease of sliding movement of the bladethrough the slot. Thus, with an abrasive element or stone which has thedesired hollow grind curvature, great pains must be taken not to inclinethe skate blade as it is being drawn or pulled through the slot, andalso lateral centering of the blade must be preserved otherwise one .ofthe two parallel ice-cutting edges becomes displaced vertically withrelation to the other edge. The average unskilled operator is unable tocontrol skate blade rocking in the slot or skate blade centering andthus such aforementioned prior art skate blade sharpening devices areseldom relied upon for full skate blade sharpening operations, butrather, they are used for touch-up" jobs. Similar limitations areprevalent in connection with various jigs which have been devised forpresenting a skate blade to be sharpened to a rotating grinding wheel bydrawing the blade through a slot.

In the latter instance, out-of-true skate blade sharpening is morelikely to occur than with pocket-type sharpening devices inasmuch as onefalse movement of the skate blade results in serious, and sometimesdeleterious, blade damage.

The present invention is designed to overcome the above-notedlimitations that are attendant upon the construction and use ofconventional skate sharpening devices regardless of whether the same bepocket-type or powered. Accordingly, in carrying out the invention,there is provided a hand drill attachment having a ro tating grindingwheel of a diameter commensurate with the desired curvature of thehollow grind which is to be applied to the skate blade, the wheel havinga drive shaft which may be conveniently received in the chuck of anelectrically-powered portable hand drill or the like. A cylindricalcasing closely surrounds the rotary abrasive grinding wheel and isformed with a longitudinally extending peripheral slot which exposes alimited peripheral area of the grinding wheel so that a skate bladewhich is drawn or pulled progressively through the slot encounters thewheel in a transverse direction to the end that the wheel will ream outthe desired hollow grind in the skating edge of the blade.

One of the principal features of the present invention resides in theprovision of a skate blade positioning assembly or unit which is capableof being removably clamped in position within the casing slot and, whenso positioned, defines a secondary skate blade guide slot which, whenthe skate blade is drawn or pulled therethrough, maintains the bladeproperly addressed to the periphery of the abrasive wheel so that therewill be neither angular tilting of the blade within the secondary slotduring grinding operations nor lateral displacement of the blade withinsaid slot. Stated otherwise, the blade will at all times during itstraverse of the secondary slot remain in a true radial plane withrespect to the abrasive wheel so that there will obtain along theskating edge of the blade a true and symmetrical hollow grind curvaturewhich leans neither to the right nor to the left and which is uniformthroughout its length. The provision of a skate sharpening device suchas has briefly been outlined above constitutes the principal object ofthe present invention.

it is a further object of the invention to provide in connection with anice skate sharpening device of the character under consideration askate-positioning unit wherein there are provided adjusting meanswhereby the width of the aforementioned secondary slot through which theskate blade is drawn or pulled may be varied. This adjusting means sprovided not for the purpose of accommodating skate blades of varyingwidths, but rather for adjusting the lateral inward spring pressure ofthe slot sides against the blade sides to attain ease of skate blademanipulation, as well as to compensate for any deterioration in springpressure which may take place after a prolonged period of use of thedevice.

The provision of an ice skate sharpening device which is extremelysimple in its construction and, therefore, may be manufactured at a lowcost; one which is comprised of a minimum number of parts and,therefore, is unlikely to get out of order; one which is rugged anddurable and, therefore, will withstand rough usage; one whichis capableof ease of assembly and dismantlement for purposes of inspection ofparts, replacement or repair; one which is small and compact and,therefore, is not only readily transportable but also may beconveniently operated while being supported entirely on the person ofthe user without requiring bench or stand support; one which requires noparticular degree of skill for its successful operation and, therefore,may be used by unskilled juvenile skaters; one which is attractive inits appearance and pleasing in its design; and one which, otherwise, iswell adapted to perform the services required of it, are furtherdesirable features which have been borne in mind in the production anddevelopment of the present invention.

Other objects and advantages of the invention, not at this timeenumerated, will become readily apparent as the nature of the inventionis better understood from a consideration of the following detaileddescription.

The invention consists in the several novel features which arehereinafter described and are more particu' larly pointed out in theclaims at the conclusion hereof.

FIG. 3 is a side elevational view of the device;

FIG. 4 is a longitudinal sectional; view taken on the line '4-4 of FIG.2; a

FIG. 5 is a transverse sectional view of that portion of the devicewhich has the rotary grinding wheel;

FIG. 6 is a top plan view of the device;

FIG. 7 is an enlarged top plan view of the skate blade positioning headwhich is employed in connection with the invention;

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 7, the viewbeing turned 90;

FIG. 9 is a transverse sectional view taken on the line 9-9 of FIG. 7;

FIG. 10 is a sectional view similar to FIG. 5 but showing a modifiedform of the skate sharpening device;

FIG. 11 is an enlarged exploded perspective view of the compositegrinding wheel housing which is employed in connection with the presentinvention;

FIG. 12 is an enlarged perspective view of the grinding wheel and shaftassembly which is employed in connection with the invention;

FIG. 13 is an enlarged, exploded perspective view illustrating thecomponent parts ofa particular skate blade positioning assembly by meansof which a skate blade to be sharpened is caused to address the grindingwheel in precise grinding position;

FIG. 14 is a diagrammatic view, entirely schematic in itsrepresentation. illustrating certain frictionallyderived skate bladeerecting phenomena whichbecome prevalent when blade-sharpeningoperations are initi: ated by application of a skate blade to thegrinding wheel of the form of the invention'which is shown in FIG. 1;and g FIG. 15 is a diagrammatic view similar to F IG. 14 butillustrating the involved phenomena when a skate blade vention which isshown in FIG. 10 of the drawings.

is applied to the grinding wheel of the form of the in- Referring now tothe drawings in detail and in partic? ular to FIGS. 1 to 3, inclusive,and also FIG. 6, a skate sharpening device embodying the principles ofthe present invention is designated in its entirety by the referencenumeral 10 and, for proper operation thereof in the sharpening of askate blade, it is designed for cooperation with a rotary chuck assemblysuch as the assembly which is fragmentarily illustrated in FIG. 1 anddesignated by the reference numeral 12. Preferably, but not necessarily,the skate sharpening device 10 is designed for home use by theindividual skate owner, utilizing a conventional portable pistol-griptype hand drill having a chuck assembly such as the one illustratedherein. Moreover, when so used, the operator will conveniently, supportthe drill in his or her lap or on a table or other support while holdingthe device 10 against rotation bodily with one hand and whilemanipulating the skate blade undergoing sharpening with the other hand,all in a manner that will be made clear presently when the nature of theinvention is better understood. It is within the purview of theinvention, however, that the device 10 may be employed in the commercialsharpening of skate blades by a small shop operator, in which case benchsupport of the hand drill orr other power tool having a chuck such asthe chuck assembly 12 may be resorted to if desired, while rotation ofthe skate sharpening device may be prevented by any suitabletorque-arresting reaction clamping means.

Still referring to FIGS. 1 to 3, inclusive, and FIG. 6, and additionallyto FIG. 4, briefly the skate sharpening device 10 involves in itsgeneral organization a tubular casing 14 which is of generallycylindrical configuration and within which there is disposed a rotaryabrasive grinding wheel16. The latter is supported on a drive shaft 18,the rear end of which is designed for reception by the chuck assembly12. A major sector of the grinding wheel 16 is enclosed withinandshielded by the casing 14, but a limited peripheralregion of thewheel is exposed for skate sharpening purposes by reason of theexistence of a peripheral slot 20 (see FIGS. 1, 2, 5, and 11) in thecasing 14. In order to control the disposition of the skate blade whichis undergoing sharpening and to apply ti to the grinding wheel 16 forsharpening purposes at a 0 angle (i.e., so that it lies in the verticaldiametric plane of the grinding wheel axis), a skate blade positioningunit or assembly 22 is removably received within the slot 20. Thisassembly 22 constitutes one of the principal features of the presentinvention and, as will be set forth in greater detail hereafte r, theassembly is so designed and is so related to the grinding wheel 16positionally' that practically noskill is required in order to bring theskate blade into proper grinding position, it being necessary only forthe operator to introduce the blade in an approximate tangentialrelation to the grinding wheel; after which the frictional force whichthe periphery of the rotating grinding wheel offers to the adjacent edgeof the skate blade which is undergoing sharpening, automatically erectsthe skate blade, so to speak, to a precise vertical position wherein theplane of the blade and the diametric plane of the grinding wheel arecoincident, thereby resulting in a precise hollow grinding operationupon the edge of the skate blade wherein the center of curvature of theblade edgeconcavity lies precisely in the median plane of the blade.Aswill also be made clear presently, the skate blade positioningassembly 22 is removably received within the slot 20 for the purpose ofhead substitution in order to accommodate skate blades of differentwidths as, for example, the blades which are associated with figureskates, hockey skates, and racing skates.

Considering the skate sharpening device in greater detail, the casing 14is comprised of three principal parts, namely, a main body portion 24,an end cap 26 (see FIGS. 1, 3 and 11), and a bearing sleeve 28. The mainbody portion includes an outer cylindrical wall 30, an annular radialand wall 32, and a rearwardly extending cylindrical wall 34 of reduceddiameter. The forward rim of the cylindrical wall 30 is closed by meansof the end cap 26 which is telescopically received within the wall 34and is provided with a radial rim flange 36 (see FIG. 4) which seats onthe rim of the wall 30. A pair of locking screws 38 (see FIG. 6) servesreleasably to hold the end cap in position on the body portion 24.

The body portion 24 of the casing 14 establishes a grinding wheelhousing within which the grinding wheel 16 rotates, the latter beingmounted on the forward end of the shaft 18 which projects axiallythrough the bearing sleeve 28 and into the housing. A clamping nut 40which s threadedly received on the extreme forward end of the shaft 18serves to force the grinding wheel 18 rearwardly against a washer 41which, in turn, bears against a shoulder 42 on the shaft. The shaft 18is rotatably supported in the casing 14 by means of a sealed ballbearing assembly 44, the outer race of which is press-fitted in anannular recess 45 in the central portion of the annular radial end wall32, and the inner race of which is straddled by the aforementionedwasher 41 and a snap ring 46 in an annular groove'in the shaft 18. Thebearing sleeve 28 is provided for the purpose of lending axial stabilityto the shaft 18 and, accordingly, this sleeve has its forward end regionthreadedly received as indicated at 48 (see FIG. 4) within therearwardly extending cylindrical wall 34 of the main body portion of thecasing 14 and supports at its rear end a shaft bushing 50 having aradial rim flange 52 which seats on the rear circular rim of the bearingsleeve 28. The bushing 50 affords a bearing support for the rear end ofthe rotatable shaft 18- at a region appreciably removed from the bearing44 so that these two bearing supports 50 and 44 maintain the shaft 18 inits proper coaxial relationship with respect to the casing 14. Theextreme rear end of the shaft 18 is formed with a reduced section 54which is designed for reception in the chuck assembly 12 of the handdrill or other power tool by means of which the skate sharpening device10 is powered.

Referring now to all views of the drawings, but with particularreference to FIGS. 1 to 9, inclusive, wherein the preferred form of theinvention is isclosed, the previously mentioned skate positioningassembly 22 is a self-contained unit andconsists of a rigid, one-piece,frame-like support (see FIG. 13) having two substantially identical,laterally spaced, arched, side wings 62 and 64, the latter beingconnected together at their ends by transverse base struts 66 and 68.The side wing 62 has formed therein a bore 70 which receives a screw 72(see FIG. 8) by means of which a shoe-like wear plate 74 having a tappedhole 76 therein may be fixedly clamped to the inside face of said sidewing 62. The side wing 64 has formed therein a socket 78 within whichthere is seated the outer end of a helical compression spring 80. Theinner end of the spring 80 projects outwards of the inner end of thesocket 78. An adjusting screw 82 projects loosely through a hole in thebottom wall of the socket 78 and has the free end of the shank receivedin a tapped hole 84 in an adjustable shoe-like wear plate 86. The shankof the screw 82 also extends loosely through the spring, and the head ofthe screw is located adjacent to the outer side surface of the side wing64 and serves to limit inward sliding movement of the screw and the wearplate 86. The wear plate 86 is spaced inwards of the inner side surfaceof the side wing 64 and is yieldingly held in place by the action of thespring 80.

As best shown in FIGS. 6, 7 and 8 of the drawings, when the two wearplates 74 and 86 are assembled upon the frame-like support 60, theyassume spacedapart positions between the two arched side wings 62 and 64with the wear plate 74 fitting against the inside face of the side wing62 and with the wear plate 86 assuming a position slightly spaced fromthe inside face of the side wing 64. In this assembled position, thesetwo wear plates define therebetween a skate bladereceiving channel orslot 88 (see FIGS. 6, 7 and 8) through which the blade is adapted to bedrawn in a longitudinal direction during blade sharpening operationswhile the edge of the blade which is undergoing sharpening contacts theperiphery of the rotating grinding wheel 16 as shown in FIG. 5.

Referring now to FIGS. 7 and 8, it will be noted that the spring 80 isinterposed between the bottomwall of the socket 78 and the wear plate 86so that this spring yieldingly biases the wear plate inwardly of theskate blade-receiving slot 88. By rotating the adjusting screw 82 in onedirection or the other, the wear plate 86 will be drawn toward the sidewing 64 or forced away therefrom, as the case may be, and thus, rotationof the screw 82 serves to adjust the effective width of the skateblade-receiving slot 88 in order to accommodate skate blades of varyingwidths.

In order to supply torque reaction to the two wear plates and preventturning motion thereof when either the clamping screw 72 or theadjusting screw 82 is rotated, each side wing 62 and 64 is formed with apair of narrow horizontal ledges 89 (see FIGS. 6, 7, 8, 9 and 13) onwhich the opposite ends of the wear plates 74 and 86 normally rest whenthey are operatively installed on the frame-like support 60.

In order releasably and removably to install the skate blade positioningassembly 22 within he peripheral slot 20 in the casing 14, one end ofthe arched side wing 64 is provided with a vertical bore 90 (see FIG.13), and a tapped socket 92 is formed in that portion of the annularradial end wall 32 which defines the bottom of the slot 20, such socketbeing for reception of a clamping screw 94 (see FIGS. 1 and 6) by meansof which the frame-like support 60, and consequently, the entire skateblade positioning assembly 22, may be fixedly secured within the slot20. The clamping screw 94 constitutes the sole fastening means for theskate blade positioning assembly 22 within the slot 20 and thus thisscrew, which is disposed at one comer of the frame-like support 60,makes it possible to install the assembly 22 within the slot only in itseffective operative position, reversal of the assembly being impossible.

A careful consideration of FIGS. 2 and 4 will reveal the fact that theperipheral slot 20 which is formed in the casing 14 and the end cap 26is cut on a small angle bias with respect to a diametric planeof thegrinding wheel 16, which is to say that the central plane of the slot 20does not pass through the longitudinal combined axis of the grindingwheel and the shaft 18. The angle involved preferably is on the order of2. Thus, when the skate blade-positioning assembly 22 is operativelyinstalled in this slot 20, the central plane of the blade-receiving slot88 is also on a small angle bias inasmuch as the entire assembly 22becomes angularly disposed when it is inserted in the slot 20.

With the assembly 22 being thus angularly inclined, it is obvious thatwhen a skate blade such as the blade B of FIG. 5 is initially insertedin the blade-receiving slot 88 as shown in dotted lines, and the edge ofthe blade is brought into contact with the periphery of the grindingwheel 16, the general plane of the blade will also be inclined withrespect to the vertical diametric plane of the grinding wheel 16, thisinclination beingschematically illustrated by the angle 0 in FIG. 14.This inclination of the skate blade is predicated upon the insertion ofthe blade into the slot 88 by the average unskilled operator, usually achild, who will push the blade into the slot in amanner that will givehimthe least resistance. The net result of this initial angularapplication of the skate blade B, to the grinding wheel 16 isschematically illustrated by dotted lines in FIG. 14 where it will beobserved that one side edge of the blade B will be brought into contactwith the rotating grinding wheel. Ordinarily, if skate blade sharpeningoperations were to continue on this angular bias, an improper hollowgrinding of blade would result. However,

, due to the relatively great frictional force which is appliedtransversely to the skate blade B due to its contact with the peripheryof the rotating grinding wheel which rotates in the counterclockwisedirection as shown by the arrow in FIG. 14, the tendency for the bladeis to erect itself so that it assumes the full-line position shown inthis view whereinthe general plane of the blade passes through thecombined longitudinal axis of the wheel 16 and the shaft 18. Inapproaching this vertical position, the side of the blade B pivots abouta horizontal fulcrum axis which is established by the adjacent lowercorner edge of the fixed wear plate 74, this fulcrum axis beingdesignated by the axis X in FIG. 14. As the blade B continues to erectitself as previously set forth, the spring-biased wear plate 86 on theopposite side of the blade B rides inwardly on the adjacent side of theblade B from the dotted line position thereof to the full-line position,this wear plate finally assuming a vertical position alongside the skateblade'while the fixed wear plate 74, of course, remains inclined. In-itsfinal erect condition, the blade assumes a floating condition, thefriction of the grinding wheel 16 tending to force the bottom portion ofthe blade to the left as viewed in FIG.-14, and the spring 80assimilating the backwardjforce which is applied to the wear plate 86.

The rate" or strength of the spring 80 is selected sothat a propercondition of bala'nce-of the blade B is attained wherein the blade issubstantially vertical or at least so nearly vertical that the hollowgrind which is effected upon the skate blade presents a center of cur Ivature which lies within the vertical diametric plane of the grindingwheel or so close thereto that-no significant canting of the hollowgrind gurvature takes place.

In FIG. 10, a slightly modified form of the invention is shown. In thisview, a skate sharpening device 110 embodies a grinding wheel 16 andv askate bladepositioning assembly 22 which are identical to thosepreviously described in connection with the form of the invention shownin FIGS. 1 through 9 and which, therefore, have been designated byidentical reference numerals so that a description thereof is deemed tobe unnecessary. The grinding wheel casing 114 of the device 110,however, is slightly different from the casing 14 of the device 10, theonly difference being in the nature of the slot 120 which is formed inthe cylindrical wall, the radial end wall, and the end cap 126 of thedevice 110. Apart from the provision of the slot 120, the two skatesharpening devices 10 and remain substantially the same and, therefore,in order to avoid needless repetition of description, similar referencenumerals but of a higher order have been applied to the correspondingparts as between the casing structure or arrangements illustrated inFIGS. 10 and 2.

Whereas, in the previously described form of the invention, the slot 20is cut in the'casing 14 on a slanting bias as heretofore mentioned, theslot in the modified form of the invention is cut in a radial directionso that it possesses no slant. However, this slot is tangentially offsetwith respect to the periphery of the grinding wheel 16 and, as a result,when the skate bladepositioning assembly 22 of the device 110 isoperatively installed in this slot, the two wear plates 74'and 86 arevertical and define therebetween a skate bladereceiving slot 188 whichis also vertical. The slot 120, and consequently, the blade-positioningassembly 122, is offset counter to the direction of rotation of thegrinding wheel 16 as schematically illustrated in FIG. 15 and,therefore, as is the case in the previously described form of theinvention, a skate blade such as the blade B, when inserted into thevertical or radially extending slot 188 as shown in dotted lines in FIG.15 will engage the grinding wheel 16 at one corner of the skate blade.However, immediately upon frictional contact between the skate blade Band the grinding wheel 16, the originally erect blade B 'will be urgedto the left as shown by full lines in FIG. 15 so that'one side thereofwill pivot about the fulcrum axis X whichis established by the adjacentlower corner edge of the wear plate 74, and come to rest in a floatinginclined position as shown in full lines in FIG. 15. In this inclinedposition,

the general plane of the skate blade B will line in a diametric planewhich passes through the combined axis of the grinding wheel 16 and itsshaft 18.

A brief comparison between the device of FIGS. 2 and 14 on theone hand,and the device of FIGS. 10 and 15 on the other hand, may be hade bystating that in the first instance the skate blade B enters the slot 88in an angularly-displaced non-radial -or secantial direction and isforced. by frictional contact with the grinding wheel into a trulyradial or vertical position. In the second instance, the skate blade Benters the slot 188 in a vertical, but non-radial, secantial directionand is forced by therotating grinding wheel into a slanting but trulyradial position. In either event, since the fully sharpened skate bladesB andd B are acted upon by the grinding wheel for blade-sharpeningpurposes while they extend radially of the grinding wheel, the netresult is the same.

It will be understood that the terms fverticalf and horizontal asemployed herein refer to directions which obtain when theskate-sharpening devices 10 or 110 are positioned as shown in FIGS. 2 to6, inclusive,

and FIG. 10 with the slots 20 or 120 being disposed at the extremeuppermost sector of the casings 14 and 114, respectively. It will alsobe understood that when a particular skate blade is undergoingsharpening with the devices of the present invention, the blade will bedrawn longitudinally through the slot 88 or 188 in the usual manner ofskate-sharpening operations with skate-sharpening devices having skatebladepositioning slots which guide the skate blade against askate-sharpening stone or wheel. Ordinarily, in using theskate-sharpening device 10 or 110, after the reduced section 54 of thegrinding wheel shaft 18 has been operatively clamped in the chuck 12 ofan electric hand drill, the trigger control of such drill will be set toits permanent on" position and the hand drill will then be placed in thelap of the user while at the same time one hand will be applied to thecasing 14 to hold the device while at the same time preventing bodilyrotation thereof due to chuck rotation. With the hand drill andskate-sharpening device thus supported, the other hand of the user mayconveniently be employed for performing the necessary skate blademanipulation in drawing or pulling the same longitudinally along thethrough slot 88 or 188 which is afforded by the skate blade positioningassembly 22 or 122.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawings or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit of the invention. For example, whereasthe slot which is provided in the casing 14 and the end cap 26 is cut ona slanting bias as previously described, it is within the purview of theinvention to fashion the wear plates 74 and 86, or their mountings, inthe assembly 22 so that these wear plates establish an inclinedskate-positioning channel 88 which initially guides the skate bladeagainst the grinding wheel in a non-erect or slanting position but inwhich these wear plates function when the skate blade is frictionallyengaged by the grinding wheel to bring the skate blade to an erectgrinding position. Therefore, only insofar as the invention isparticularly pointed out in the accompanying claims in the same to belimited.

Having thus described the invention what I claim as new and desire tosecure by letters patent is:

l. A portable skate blade sharpening device adapted to hollow grind theeffective supporting edge of a skate blade and comprising a drive shafthaving a rear end adapted for connection to a power drive source, acircular abrasive grinding wheel mounted fixedly on the front end of theshaft, a tubular casing encompassing said wheel and a portion of thedrive shaft, said casing having a rear end wall through which the driveshaft projects rearwardly, and a front wall, bearing means interposedbetween the drive shaft and casing and serving rotatably to support theshaft and the wheel, said casing and rear walls being relieved toprovide a longitudinally extending blade-receiving slot which exposes alimited peripheral region of the wheel for transverse applicationthereto of the skate blade at such time as the edge region of the latteris drawn progressively and longitudinally through said slot, and bladepositioning means removably mounted within said slot and defining asecondary slot for sliding reception therein of the skate blade, oneside wall of said secondary slot being laterally yieldable and normallyserving to displace the skate blade and compress the same against theopposite side wall of said secondary slot, said latter side wall beingfixed with respect to the casing.

2. A portable skate blade sharpening device as set forth in claim 1 andwherein the yieldable side wall is disposed on the side of the secondaryslot from which points on the periphery of the grinding wheel recededuring wheel rotation.

3. A portable skate blade sharpening device as set forth in claim 2 andwherein said blade positioning means comprises a fixed wear plate and amovable wear plate, said wear plates defining therebetween saidsecondary slot, the opposed faces of said wear plates establishing saidfixed and yieldable side walls respectively, and spring means yieldinglyurging said yieldable wear plate toward said fixed wear plate.

4. A portable skate blade sharpening device as set forth in claim 3 andwherein the side walls of said secondary slot normally lie in parallelspaced apart planes which are inclined at a small angle relative to adiametric plane of the grinding wheel, the direction of inclination ofsuch walls being such that normally they serve to guide the skate bladeagainst the periphery of the grinding wheel at a point in advance ofsaid diametric plane relative to the rotary motion of the wheel.

5. A portable skate blade sharpening device as set forth in claim 3 andwherein the forward end of the drive shaft is threaded and projectsaxially through the grinding wheel, a clamping nut is received on saidthreaded end of the shaft and serves to clamp the wheel against anannular shoulder on the shaft, and said front end wall is in the form ofa removable end cap which seats on the forward rim of the outercylindrical casing wall and which, when removed therefrom, affordsaccess to said clamping nut for grinding wheel replacement purposes.

6. A portable skate blade sharpening device as set forth in claim 5 andwherein said bearing means is in the form of a sealed ball bearing unitwhich is pressfitted centrally in said rear end wall, and the casingincludes an elongated rearwardly extending bearing sleeve which isconcentric with the drive shaft and which carries a shaft bushing at itsrear end.

7. A portable skate blade sharpening device as set forth in claim 6 andwherein said fixed and movable wear plates are operatively mounted on aframe-like support which fits snugly within said slot in the casing, andsaid support is removably secured in position within said latter slot bymeans of a clamping screw which is threadedly received in a laterallyoffset tapped hole in one of the walls of said casing whereby reversalof the support, and consequently, the wear plates, is prevented.

8. A portable skate blade sharpening device as set forth in claim 7 andwherein said spring means comprises a helical compression spring whichis interposed between the movable wear plate and said frame-likesupport, and a compression adjusting screw projects loosely through aportion of said support and also through said compression spring and isthreadedly received in said movable wear plate.

9. A portable skate blade sharpening device as set forth in claim 3 andwherein the side walls of said secondary slot normally lie in parallelspaced apart planes which are parallel to a diametric plane of thegrinding wheel and which are equally spaced from a medial plane which isoffset laterally from said diametric plane in the direction of advancingpoints on the periphery of the rotating grinding wheel.

1. A portable skate blade sharpening device adapted to hollow grind theeffective supporting edge of a skate blade and comprising a drive shafthaving a rear end adapted for connection to a power drive source, acircular abrasive grinding wheel mounted fixedly on the front end of theshaft, a tubular casing encompassing said wheel and a portion of thedrive shaft, said casing having a rear end wall through which the driveshaft projects rearwardly, and a front wall, bearing means interposedbetween the drive shaft and casing and serving rotatably to support theshaft and the wheel, said casing and rear walls being relieved toprovide a longitudinally extending blade-receiving slot which exposes alimited peripheral region of the wheel for transverse applicationthereto of the skate blade at such time as the edge region of the latteris drawn progressively and longitudinally through said slot, and bladepositioning means removably mounted within said slot and defining asecondary slot for sliding reception therein of the skate blade, oneside wall of said secondary slot being laterally yieldable and normallyserving to displace the skate blade and compress the same against theopposite side wall of said secondary slot, said latter side wall beingfixed with respect to the casing.
 2. A portable skate blade sharpeningdevice as set forth in claim 1 and wherein the yieldable side wall isdisposed on the side of the secondary slot from which points on theperiphery of the grinding wheel recede during wheel rotation.
 3. Aportable skate blade sharpening device as set forth in claim 2 andwherein said blade positioning means comprises a fixed wear plate and amovable wear plate, said wear plates defining therebetween saidsecondary slot, the opposed faces of said wear plates establishing saidfixed and yieldable side walls respectively, and spring means yieldinglyurging said yieldable wear plate toward said fixed wear plate.
 4. Aportable skate blade sharpening device as set forth in claim 3 andwherein the side walls of said secondary slot normally lie in parallelspaced apart planes which are inclined at a small angle relative to adiametric plane of the grinding wheel, the direction of inclination ofsuch walls being such that normally they serve to guide the skate bladeagainst the periphery of the grinding wheel at a point in advance ofsaid diametric plane relative to the rotary motion of the wheel.
 5. Aportable skate blade sharpening device as set forth in claim 3 andwherein the forward end of the drive shaft is threaded and projectsaxially through the grinding wheel, a clamping nut is received on saidthreaded end of the shaft and serves to clamp the wheel against anannular shoulder on the shaft, and said front end wall is in the form ofa removable end cap which seats on the forward rim of the outercylindrical casing wall and which, when removed therefrom, affordsaccess to said clamping nut for grinding wheel replacement purposes. 6.A portable skate blade sharpening device as set forth in claim 5 andwherein said bearing means is in the form of a sealed ball bearing unitwhich is press-fitted centrally in said rear end wall, and the casingincludes an elongated rearwardly extending bearing sleeve which isconcentric with the drive shaft and which carries a shaft bushing at itsrear end.
 7. A portable skate blade sharpening device as set forth inclaim 6 and wherein said fixed and movable wear plates are operativelymounted on a frame-like support which fits snugly within said slot inthe casing, and said support is removably secured in position withinsaid latter slot by means of a clamping screw which is threadedlyreceived in a laterally offset tapped hole in one of the walls of saidcasing wHereby reversal of the support, and consequently, the wearplates, is prevented.
 8. A portable skate blade sharpening device as setforth in claim 7 and wherein said spring means comprises a helicalcompression spring which is interposed between the movable wear plateand said frame-like support, and a compression adjusting screw projectsloosely through a portion of said support and also through saidcompression spring and is threadedly received in said movable wearplate.
 9. A portable skate blade sharpening device as set forth in claim3 and wherein the side walls of said secondary slot normally lie inparallel spaced apart planes which are parallel to a diametric plane ofthe grinding wheel and which are equally spaced from a medial planewhich is offset laterally from said diametric plane in the direction ofadvancing points on the periphery of the rotating grinding wheel.